Telephone instrument.



G. BOISSONNAULT.

I TELEPHONE INSTRUMENT.

APPLICATION man DEC-6. 1916-- lfimfil 3'0 "Patented July 24, 1917.

a nve Wroz a ibis.

eA-sroiv BOISSONNAULT, or new YORK, N. Y., hSSIGNOR TOMICROPI-IO-DETEC'IOR 00., I1vc., on NEW YORK, N. Y., A coRP'o'RATIoN 01?NEW YoRK.

TELEPHONE INSTRUMENT.

To all whom it may concern: v

Be it known that I GAs'roN BOISSON- NAULT, a subject of the King ofGreat- Britain, residing at New York city, in the county and State ofNew York, have invented certain new and useful Improvements in TelephoneInstruments, of which the following is aspecification.

My invention relates to telephone instruments, particularly telephonetransmitters and it consists in so constructing and arranging theelements which make up the instrument that its adjustment may beconveniently accomplished, preferably without opening the case.

Figure l is a central vertical sectional view of a transmitter embodyingmy invention.

Fig. 2 is a face view of the instrument,

with the cover, the diaphragm and the carbon balls removed.

Fig. 3 is a face view of the rear side of the instrument, showing alsothe lead wires. A demand has arisen in the art for a very sensitiveinstrument and a number of devices intended to meet that demand havebeen devised.

Such an instrument requires an exceedingly delicate adjustment. Thecarbon block, generally used to support the granular or ball carbon,must be so adjusted as to approach the diaphragm as closely as possible,but not so close that the vibration of the diaphragm will cause it tomake contact with the block, since the contact should be with thegranular or ball carbon and contact with the block itself will interferewith that sensitive variation of the current which is necessary for thebest results. At the same time said block and diaphragm should be soclose that the granular or ball carbon will be retained in itsappropriateposition.

Heretofore, adjustmenthas been secured by opening the case and placingone or more disks of mica between the block and its support, but thatmethod is faulty in that it requires considerable time and, in replacingthe cover or other parts, an adjustment once satisfactory is liable tobe disturbed. Again, for very sensitive instruments carbon blocksSpecification of Letters Patent.

Patented July 241;, 1911?.

Application filed December 6, 1916. Serial No. 135,326.

with a series of depressions have been used, each depression filled orpartly filled with carbon balls. But to secure good results wlth suchapparatus, each depression should be occupied by the same number ofcarbon balls and the adjustment of such series, when accomplished, as itmust be, by the adjustment of the carbon block, or by changing thenumber of balls in each recess, is a matter of much difiiculty.

Tomeet the difiicultyand render a more perfect adjustment possible andat the same time more easily and economically accomplished, I havedevised an instrument in which a single depression is provided with acarbon pencil or post located behind the space occupied by the carbonballs and so arranged that it 'may be advanced or drawn backindependently of any movement of the block, to cause the carbon balls infront of it to press more tightly or loosely against the diaphragm, togive the desired sensitive'ness. This arrangement permitsme to adjustthe carbon block to a desired position and then complete the adjustmentfor sensitiveness without again moving the carbon block from thepreferred position.

In additionto this feature, I prefer to provide extensions from theparts to be adjusted, passing through the case to points where it orthey may be reached and oper ated without opening the case, thuspermitting the adjustment to be made after the parts are completelyassembled and by means which may be graduated to the finest lines. Iprefer to pass the extensions through the case, but the same idea wouldbe exhibited in a device in which the extensions did not so extend butthe case was so constructed as to leave the parts accessible foradjustment without opening the case, for instance if the case hereinshown were so deep that the parts did not extend through it, but theaperture was sufficiently large for the insertion of a screw driver toturn said extensions.

In the embodiment shown, 1 is the case of the instrument, preferablygiven a cup shape, with the edge threaded to receive the cover 2 whichis pierced at 3 to permit the passage of sound waves. The case 1 isapertured, preferably centrally, to receive the extensions of the carbonsupporting parts. The carbon diaphragm 4 is held between the cover andthe case, resting upon the edge of the case and clamped thereto by thecover ring which is suitably shaped to perform that function. In theaperture in the case I first seat an insulator 5, of mica, hard rubberor other suitable substance, and through that insulator, I prefer toextend a sleeved keeper 6, flanged on one side, threaded on.

the other end and provided with a nut 7 for looking it in position, thecircuit arm or terminal 8 being usually placed on said keeper, betweenthe insulator and the nut and locked in position by turning down thenut. Then I provide a carbon block 9, preferably fastened to anextension 10, which is threaded to turn in threads cut in the interiorof the sleeved keeper 6, and provided with a lock nut 11 which may beturned down on the extended part and against the end of the keeper (3.The face of the carbon block is recessed, preferably centrally as at 12,to receive the carbon contacts 18, in the form of polished balls ofminute diameters, and to render the adjustment still more delicate, Iprefer to extend the recess in block 9 entirely through it and throughits extension 10 and to mount therein a carbon post or pencil 14, withan extension 15, threaded in the aperture in the block extension 9 andprovided with a lock nut 16. The outer extremity may be provided with. aslot or groove as shown, or any other means for conveniently turning it.Binding posts 17, 18 and lead wires 19, 20 are too well known to needparticular description.

It will be noted that the extension 10 of block 9 and the extension 15of the carbon pencil 14, both project beyond the case 1,

so that they may be readily operated without opening that case. Therespective parts of the instrument having been assembled, and this maybe done by unskilled labor, the skilled adjuster connects the instrumentto his testing circuit, takes it in his hand and turns in the extension10 until the block 9 reaches the desired proximity to the diaphragm 4and looks it in position by turning down nut 11. Then he adjusts theposition of the ball contacts by turning in the is required, take theinstrument apart, make the change, put it together, try again, andperhaps again; but with it in hand the trial may be made, the changeaccomplished without breaking the circuit or other manipulation otherthan turning in or out the extensions which are ready to the finger forthat purpose.- 7 a Then too, if by jar or other rough handling, theadjustment is disturbed, or the use to which the instrument is to be putre- .quires a different adjustment, such readjustment may be made asconveniently and quickly as the original adjustment and in the samemanner, by simply manipulating the extensions 10 and 15. V In fact manyadjustments may be made by turning extension 10 alone, since that incarrying the block 9 inward or, outward, will also carry the carbonpencil 14 inward or outward and increase or decrease the pressure of thecar bons upon the diaphragm, according to the direction of the movement.

So too, many adjustments may be made by simply projecting the carbonpencil 14, or drawing it back, without altering the position of theblock 9 and this may be done even when the extensions do not. extendthrough the case.

It will be manifest to any one of any mechanical knowledge, that theforms of the instrumentalities employed may be varied almost at willwithout departing from the spirit of the idea, and I do not intend to belimited to the form or arrangement shown, that being but'one of the manywhich may be developed when the idea has been once made clear. I

What I claim and desire to secure by Letters-Patent, is

1. In a telephone instrument, a case,,a diaphragm, a series of carbonparticles contacting with said diaphragm, a support for said carbonparticles, in the form of a recessed block containing a carbon pencillocated in the recess in said block, and an extension from said pencilprojecting through the case and accessible from the outside thereof andadjustable inward or outward.

:2. In a telephone instrument, a case, a diaphragm within the case, acarbon block mounted Within the case and provided with a centralaperture and an extension projecting through an aperture in the case, akeeper interposed between the said extension and the case and insulatedtherefrom but threaded to the extension, a carbon pencil projecting intothe block recess and provided with an extension threaded in the blockextension and projecting beyond the case, particles of carbon seated inthe block recess and impinging upon the diaphragm and means for securingthe extensions in varied positions, all combined substantially as setforth.

3. In a telephone instrument, a case, a advancing or drawing back saidcarbon diaphragm supported from said case, a repencil. cessed block alsosupported from said case, In testimony whereof, I have signed my 10 andprovided with an adjustable carbon penname to this specification this4th day of 5 oil located in said recess, a series of carbon December,1916.

particles also located in said recess but in front of the carbon pencil,and means for GASTON BOISSONNAULT.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of .Batents, Washington, D. G.

